[sickoflibs]

RE :”Correlation is not causation..It’s fully possible that rather than exercise reducing dementia, that there is some common mechanism that increases dementia and makes exercise more difficult.”

The cases I am referring to involve arthritis with overweight as the start leading to strokes or heart attacks and or broken bones,

The dementia clearly lagged in time multiple physical problems that forced reduction in physical activity.

Ambiguity in cause and effect is resolved by order in time.

again I would add isolation as a partial cause.

[jdege]

The dementia clearly lagged in time multiple physical problems that forced reduction in physical activity.

Which only indicates that the process that leads from our hypothetical actual cause to dementia takes longer than than the process that leads to physical problems.

There's a reason Alzheimer's is being called "Type 3 Diabetes".